The present invention relates to an apparatus and method for rapid flash-like volatilization of high and low vapor pressure components from liquid or solid emanators, which are in contact with a point or localized heat source. Vaporization is promoted by a geometrically small electrically resistive heater material with variable activation for pulsed or cyclic heating of the emanating surface containing the volatile components.
The field of the invention is primarily directed towards the treatment of air for fragrancing, odor elimination, treatment for insects or pests, air sanitization, air and surface antibacterial or antimicrobial treatment, or other ambient air or surface modification by way of gas or vapor distribution. Applications include devices that are portable (e.g. wearable or carried on an individual's belt), fixed for localized treatment (e.g. covering a relatively small area), or fixed for wider space treatment (e.g. covering an entire room of a house or building). Other fields of use could include commercial and other public environments requiring air or surface modification by gaseous treatment.
Air modification and treatment has been a part of dwelling, recreational, work, and other indoor and localized outdoor environment aesthetics and functionality throughout history. An inherent problem has been that aesthetic or functional volatiles with sufficiently high vapor pressure to adequately treat the environment by unaided means are limited in number and their treatment benefit. As a result there has been a long history of the use of heat to assist in the vaporization of higher molecular weight and lower vapor pressure compounds.
The use of heat increases the range of aesthetic and functional compounds that can be used for air quality management. Some of the first would have used flame (candle systems, stovetops, etc.). Although effective and still in use today, heat from a flame can be difficult to use because the magnitude of heat is difficult to regulate, and a flame typically has wide fluctuations of temperature ranges. Other problems include the affect on larger surfaces, i.e. unintended areas may be raised in temperature, the soot from a flame can blacken components, a flame can give off an unpleasant odor, the solution to be volatized can be rapidly degraded, and there is little adjustment. As a result, many materials are eliminated for use with flame systems.
In addition to flame based systems, there have emerged chemical heat emanation enhancers. Many well-known and simple chemistries are available as described in U.S. Pat. Nos. 6,248,257 and 6,289,889, and include calcium oxides, aluminum copper sulfate, potassium chlorate, calcium sulfate, iron oxide, acids and bases, and others. Chemical heat sources suffer from difficulties in closely controlling temperature and an inability to easily or reversibly stop the reaction.
Another generation of delivery methods includes devices such as compressed gases or aerosols, which propel minute droplets creating great aggregate surface area for volatilization of a liquid composition into the air. These systems work well for instant and situational applications, but present difficulties for continuous air treatment. A simple set of technologies to address this interest area have been dispensing devices with open or semi-closed supported gelatinous, fibrous, or other material of absorbed or adsorbed actives and enhancers that promote passive, unheated emanation by increased surface area. The needed large surfaces cause these products to be of limited use, especially for wearable devices.
Other passive metering systems that have emerged and have been used include semipermeable membranes, wicks, capillaries, porous materials or other fluidic transport and emanating surfaces. Other products such as deodorant and sublimation blocks are also used for dispensing air-treating vapors into the atmosphere by evaporation. The performance of these systems varies widely, and although there are hybrid systems of new materials and designs that promote vaporization by passive methods, they can suffer from the same challenges as do gel and fibrous systems.
There has been increasing use of electrified systems to promote enhanced volatilization, through the use of heat, air movement, electromechanical aerosolizers, or other methods or combinations. Heat and/or airflow have been combined with many of the passive air modification methods mentioned above. The added system energy has sometimes provided more optimal delivery performance. Although these systems can be generally successful, they leave important performance characteristics unaddressed.